Hyperbaric Chamber Therapy for Autism: What the Research Shows

Current evidence does not show that hyperbaric oxygen therapy (HBOT) improves the core symptoms of autism. A 2016 Cochrane review found no evidence of benefit, and Europe's hyperbaric medicine consensus conference recommends against using HBOT for autism spectrum disorder (ASD). One 2009 trial of mild pressure reported improvements, but later controlled studies, including a sham-controlled trial using 100% oxygen at a higher pressure, did not confirm them.

Parents who search for "autism hyperbaric chamber therapy" usually want to know two things: does it work, and is it safe? This article summarises what the research found, what the guidelines say and what to ask your child's doctor if the topic comes up.

Does Hyperbaric Oxygen Therapy Help Autism?

The short answer from the highest-quality sources is no, based on the evidence available so far.

• Cochrane (2016). The Cochrane review by Xiong and colleagues searched for randomised trials up to December 2015. Only one trial, with 60 children, met its criteria. The authors concluded: "To date, there is no evidence that hyperbaric oxygen therapy improves core symptoms and associated symptoms of ASD."
• European Committee for Hyperbaric Medicine (ECHM). At its Tenth European Consensus Conference in 2016, the ECHM stated that evidence of a lack of clinical effect allowed it to recommend not using HBOT in autism spectrum disorders. This was a Type 1 recommendation, its strongest category, based on Level B evidence.
• Undersea and Hyperbaric Medical Society (UHMS). Autism is not on the UHMS list of accepted indications. UHMS also describes "mild" hyperbaric treatment below 1.5 ATA as unproven.
• U.S. Food and Drug Administration (FDA). In its last consumer update on HBOT, the FDA listed 13 conditions for which it had cleared hyperbaric chambers, and autism was not one of them. Its consumer guidance stated that HBOT devices "are not proven to cure cancer, Lyme disease, autism or Alzheimer's disease."

For the conditions HBOT is accepted for, see our guide to HBOT indications.

Why Was HBOT Proposed for Autism?

Before the controlled trials, several uncontrolled studies had reported improvements in children with autism after hyperbaric treatment, according to the authors of the 2009 Rossignol trial. The Cochrane authors note it has been suggested that HBOT may ease "biochemical dysfunction" and symptoms in ASD. However, they also judged the treatment to have limited biological plausibility for autism. Uncontrolled reports cannot separate the effect of the chamber from expectations, extra attention or ordinary development, which is why randomised trials with a sham comparison matter.

What the Controlled Studies Found

The positive trial

The 2009 Rossignol trial was randomised and double-blind, and it did report improvements. Two points help put it in context:

• The "treatment" was very mild: 1.3 atmospheres with 24% oxygen, only slightly more oxygen than normal air (21%). Medical HBOT, as defined by UHMS, uses at least 2.0 ATA and medical-grade oxygen over 99% pure.
• Its findings have not been confirmed by later controlled studies. One study of the same pressure and oxygen level (Jepson 2011) found no consistent behavioural effects.

The negative and neutral trials

The Thai trial by Sampanthavivat and colleagues tested a stronger dose, 100% oxygen at 1.5 ATA, against a sham. Children in both groups improved on the Autism Treatment Evaluation Checklist, with no significant difference between them. The authors concluded that "no overall clinically significant benefit from HBOT could be shown."

That result matters for families. If children improve just as much after sham sessions, the improvement is probably not coming from the oxygen. It may reflect expectation, the structure of regular sessions, time passing or other therapies happening at the same time.

Is Hyperbaric Oxygen Therapy Safe for Children With Autism?

In the trials above, treatment was generally well tolerated. But "well tolerated" is not the same as "no risk":

• The Cochrane review found significantly more side effects in children given HBOT than in those given sham treatment. These were minor-grade ear barotrauma events, meaning pain or injury from pressure on the eardrum.
• Treatment requires a child to equalise their ears as pressure changes and to stay inside an enclosed chamber for each session.
• General HBOT risks include temporary short-sightedness and, rarely, oxygen-induced seizures. See our full guide to HBOT side effects and safety.
• Fire is a real hazard with pressurised oxygen. The FDA has warned that fires and explosions have occurred in chambers not reviewed by the FDA at unaccredited facilities, and in 2025 told providers it was aware of fires causing serious injuries and deaths.

What Has Changed With the FDA?

Families may notice that some FDA pages cited online are gone. In late December 2025 the FDA retired its page "Be Aware of Potentially Dangerous Products and Therapies that Claim to Treat Autism", which had named hyperbaric oxygen therapy among products making improper claims. An HHS spokesperson described the removal as "a routine clean up of dated content." By September 2026 the FDA's consumer update on HBOT was also no longer on fda.gov.

Removing a web page does not change the research findings above. Autism was not among the conditions for which the FDA had cleared hyperbaric chambers, and Medicare's HBOT coverage list does not include it.

"Mild" Chambers Versus Medical HBOT

The 1.3 ATA sessions tested in the Rossignol and Jepson studies fall into what UHMS calls "mild" hyperbaric treatment, below 1.5 ATA. UHMS notes that mild sessions usually deliver well under 95% oxygen, often through masks that do not seal, and are generally not prescribed or supervised by a physician. The FDA has cleared soft zippered chambers only to treat altitude sickness. Our comparison of HBOT and mild hyperbaric therapy explains the differences.

Questions to Ask Your Child's Doctor

If someone recommends hyperbaric treatment for your child, these questions can help you and your child's paediatrician or developmental specialist discuss it:

1. What exactly is expected to improve, and how will we measure it before and after?
2. How does this fit with the evidence? The Cochrane review found no benefit, and the ECHM recommends against it. What makes this case different?
3. What pressure and oxygen level would be used, in what type of chamber, and who would supervise?
4. What are the specific risks for my child, including ear problems, anxiety in an enclosed space and any seizure history?
5. Is this part of a registered clinical trial with ethics approval, or a commercial service?
6. What would it cost in time and money, and would it take time away from support your child's care team already recommends?
7. Is the facility accredited, and does it follow fire safety rules for pressurised oxygen?

A good clinician will welcome these questions and answer them directly.

The Bottom Line

HBOT has a clear role in treating conditions such as decompression sickness, carbon monoxide poisoning and some non-healing wounds. For autism, the best available evidence has not shown benefit, a sham-controlled trial found no difference, and European hyperbaric specialists recommend against it. Decisions about autism support are best made with your child's own care team. You can also read what hyperbaric oxygen therapy is and how it works.

Sources

• Xiong T, Chen H, Luo R, Mu D. Hyperbaric oxygen therapy for people with autism spectrum disorder (ASD). Cochrane Database of Systematic Reviews. 2016;10(10):CD010922.
• Mathieu D, Marroni A, Kot J. Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment. Diving and Hyperbaric Medicine. 2017;47(1):24-32.
• Mathieu D, Marroni A, Kot J. Correction to: Tenth European Consensus Conference on Hyperbaric Medicine: recommendations for accepted and non-accepted clinical indications and practice of hyperbaric oxygen treatment. Diving and Hyperbaric Medicine. 2017;47(2):131-132.
• Rossignol DA, Rossignol LW, Smith S, Schneider C, Logerquist S, Usman A, et al. Hyperbaric treatment for children with autism: a multicenter, randomized, double-blind, controlled trial. BMC Pediatrics. 2009;9:21.
• Jepson B, Granpeesheh D, Tarbox J, Olive ML, Stott C, Braud S, et al. Controlled evaluation of the effects of hyperbaric oxygen therapy on the behavior of 16 children with autism spectrum disorders. Journal of Autism and Developmental Disorders. 2011;41(5):575-588.
• Sampanthavivat M, Singkhwa W, Chaiyakul T, Karoonyawanich S, Ajpru H. Hyperbaric oxygen in the treatment of childhood autism: a randomised controlled trial. Diving and Hyperbaric Medicine. 2012;42(3):128-133.
• Undersea and Hyperbaric Medical Society, Indications for hyperbaric oxygen therapy
• U.S. Food and Drug Administration, Hyperbaric oxygen therapy: get the facts (consumer update, content current as of 26 July 2021; archived copy)
• U.S. Food and Drug Administration, Follow instructions for safe use of hyperbaric oxygen therapy devices: letter to health care providers (25 August 2025)
• Diament M. FDA pulls warning about "potentially dangerous" autism therapies. Disability Scoop. 20 January 2026.
• Centers for Medicare & Medicaid Services, National Coverage Determination 20.29: Hyperbaric Oxygen Therapy

This article is for information only and is not medical advice. HBOT is not an FDA-cleared treatment for autism. Decisions about your child's care should be made with qualified professionals who know your child.